[jdk21u-dev] RFR: 8349378: Build splashscreen lib with SIZE optimization

[Matthias Baesken]

Header is a different one in 21u-dev

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Commit messages:
 - Backport c2fc94782669ae1645014ee3bfeba957dbff4669

Changes: https://git.openjdk.org/jdk21u-dev/pull/1903/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1903&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349378
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1903.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1903/head:pull/1903

PR: https://git.openjdk.org/jdk21u-dev/pull/1903